I've never had to check any of the thin plywoods I've bent. Trimming to size after bending will make it easier. If you're still having troubles after that, I'd suggest steaming it. It won't take much, maybe 30 seconds to a minute in a steam box but that should make it more flexible. Also, as I said, trying to "prebend" will make it much easier. Bend it for a couple days at a slightly larger radius than you need so that when you bend down to the final form it will already be "stretched" such that it's less likely to crack.